In general, instant film is designed to protect itself during early development. When the photo ejects, rollers spread a chemical reagent over the film; that reagent includes a light-blocking component (often called an opacifier) that shields the image while it develops. As development completes, that blocker becomes transparent so the picture can be seen.

So a separate film shade is usually not strictly required for the basic chemistry to work. That said, keeping freshly ejected film out of strong light is still sensible, especially with older or less consistent film stocks, because they can be more sensitive or less reliable than fresh film. If you have old stock, gentle handling and shielding it from bright sunlight is a good precaution.

For newer Impossible Project/modern Polaroid film, the same general idea applies, but practical behavior can vary by film generation. If in doubt, let the photo develop face down or in a dimmer place after ejection.